A model for OJ287 has been proposed consisting of two orbiting black holes in order to explain its optical light curve extending for more than 100 yr. In this model optical outbursts occur soon after the secondary has impacted on the accretion disk of the primary. Information on exact timing of six such occurrences is enough to produce a unique solution of the orbit. The full orbit determination became possible after the 2005 major outburst for the first time. After this we can test whether the orbital period becomes shorter at the rate predicted by Einstein, due to emission of gravitational waves. This test has just been carried out. The beginning of the next optical outburst was predicted by the exact orbit solution at September 13, 2007 if the orbit decays according to Einstein's theory, and 20 days later if no such decay exists. We report nightly optical observations of OJ287 in early September 2007. A very rapid flux rise began in OJ287 on September 13, leading to the highest optical brightness in twenty years, with the exception of a short period during the 2005 outburst. Considering the uncertainties both in the model and in timing of observations, this leads to the confirmation of the energy loss at the rate predicted by General Relativity at the accuracy level of 10 %. The observation also confirms the precession rate of the binary orbit as 39 degrees per period, and gives the mass of the primary as 18 billion solar masses. This is one of the first tests of General Relativity at the limit of strong gravitational fields.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2007